Why do older adults often perform better on vocabulary and general-information tests than on speed-based tests?

Older adults often perform better on tests of vocabulary and general information than on speed-based tasks due to the distinction between two types of intelligence: fluid intelligence and crystallized intelligence.1

• Fluid Intelligence: This involves the ability to manipulate abstract concepts and process new information quickly. It tends to decline from adolescence through middle age, and performance on tasks requiring speed or rapid central nervous system processing often decreases with age.213
• Crystallized Intelligence: This reflects accumulated cultural knowledge and intentional learning. Unlike fluid intelligence, crystallized intelligence typically increases throughout adulthood. Because tests of vocabulary and general information rely on this store of accumulated knowledge rather than rapid processing, older adults often perform as well as or better than younger individuals on these assessments.1342

Furthermore, research indicates that when older adults are given sufficient time to complete tasks that are not heavily dependent on speed, their performance is often comparable to that of younger adults. Age-related differences in performance are most pronounced when tasks require a fast pace, but older learners often show marked improvement when allowed to regulate the speed of a task themselves.41